Pump assembly

ABSTRACT

An improved pump assembly includes intake passage which conduct fluid from a reservoir assembly to radially opposite sides and opposite ends of a rotor assembly. To provide controlled reduction in velocity and corresponding increase in pressure as the fluid flows through intake passages toward the rotor assembly, the intake passages increase in cross sectional area in the direction of flow. A bypass valve directs a flow of fluid from the pump assembly to an auxiliary external system when a main external system is shut off. The rate of fluid flow to the auxiliary and main external systems is maintained at a predetermined maximum rate by a flow control valve assembly which diverts fluid from a discharge passage to the intake passages in response to a predetermined pressure drop as fluid flows through a nozzle at the predetermined maximum rate. When the pump assembly is to be used in different environments, the direction in which the pump assembly is adapted to be driven can be reversed by changing the orientation of the rotor assembly and end plates of the pump assembly. This adaptability of the pump assembly to different environments is enhanced by the reservoir assembly which can be rotated to any one of a plurality of positions relative to the pump assembly.

United States Patent [72] Inventor Clark A. Searle Marshall, Mich. [21] Appl.No. 855,689 [22] Filed Sept.5, 1969 [45] Patented Jan. 4,1972 [73] Assignee Eaton Yale & Towne, Inc.

Cleveland, Ohio [54] PUMP ASSEMBLY 9 Claims, 17 Drawing Figs.

[52] U.S.Cl 418/15, 418/39, 418/225, 417/300, 417/304 [51] lnt.Cl ..F01c13/00, F01c 21/00, F04c 15/00 [50] FieldofSearch 417/300, 308, 310;418/15, 39, 74, 149, 209, 225; 103/136 A,161B;91/121 [56] References Cited UNITED STATES PATENTS 3,439,623 4/1969 Dietrichetal. 417/310 1,087,181 2/1914 Pitman 418/39 2,899,941 8/1959 Adams..... 417/310 2,955,542 10/1960 Gaubatz 418/149 2,981,067 4/1961 Clarketal.... 417/300 3,059,580 10/1962 FarrelletaL. 417/300 3,384,020 5/1968 Searle 417/300 j ll L 4 3,403,630 lO/l968 Clark etal.

Primary Examiner-William L. Freeh Assistant Examiner-John J. Vrablik AttorneyYount and Tarolli ABSTRACT: An improved pump assembly includes intake passage which conduct fluid from a reservoir assembly to radially opposite sides and opposite ends of a rotor assembly. To provide controlled reduction in velocity and corresponding increase in pressure as the fluid flows through intake passages toward the rotor assembly, the intake passages increase in cross sectional area in the direction of flow. A bypass valve directs a flow of fluid from the pump assembly to an auxiliary external system when a main external system is shut off. The rate of fluid flow to the auxiliary and main external systems is maintained at a predetermined maximum rate by a flow control valve assembly which diverts fluid from a discharge passage to the intake passages in response to a predetermined pressure drop as fluid flows through a nozzle at the predetermined maximum rate. When the pump assembly is to be used in different environments, the direction in which the pump assembly is adapted to be driven can be reversed by changing the orientation of the rotor assembly and end plates of the pump assembly. This adaptability of the pump assembly to different environments is enhanced by the reservoir assembly which can be rotated to any one of a plurality of positions relative to the pump assembly.

PATENTED M 41912 $632238 INVENTOR. CLARK A. SEARLE AI'I'OP/VEXS PATENIEU m 4.872

SHEET 5 OF 8 FIGH FIGB

I NVENTOR.

K M C PUMP ASSEMBLY The present invention relates generally to a fluid pump assembly and more particularly to a pump assembly for supplying a relatively large volume of high-pressure fluid to an external system, such as a power steering unit.

It is an object of this invention to provide a new and improved pump assembly which is compact and adapted to provide a relatively large fluid flow rate to an external system, as a power steering unit.

Another object of this invention is to provide a new and improved pump assembly having a large capacity so that it can be efficiently operated at a relatively low speed.

Another object of this invention is to provide a new and improved pump assembly having intake passages which provide a controlled reduction in fluid flow velocity to thereby increase the pressure at inlets to a pumping chamber of the pump assembly.

Another object of this invention is to provide a new and improved pump assembly having intake passages shaped to provide relatively little resistance to fluid flow to the pumping chamber.

Another object of this invention is to provide a new and improved pump assembly which is internally pressure balanced due to the provision of opposite pumping sections and wherein a separate fluid supply system is provided for each of the pumping sections.

Another object of this invention is to provide a new and improved pump assembly in accordance with the preceding paragraph and having end plates which are pressure balanced to minimize deflection of the end plates.

Another object of this invention is to provide a new and improved pump assembly which includes a valve assembly for bypassing fluid to an auxiliary external system when a main external system is shut off.

Another object of this invention is to provide a new and improved pump assembly in accordance with the preceding paragraph wherein the pump assembly includes a valve assembly for limiting the flow of fluid to both the main and auxiliary external systems.

Another object of this invention is to provide a new and improved pump assembly which is versatile so as to be adaptable to many different mounting and installation conditions and which is adaptable to be driven in either one of two opposite directions.

Another object of this invention is to provide a new and improved pump assembly having a reservoir assembly which is adapted to be mounted in a plurality of positions relative to the pump assembly.

These and other objects and features of the invention will become more apparent upon a reading of the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is an elevational view of a pump system constructed in accordance with the present invention and including a pump assembly with a reservoir assembly mounted thereon;

FIG. 2 is a partially broken away elevational view illustrating the structure of a filter located in the reservoir assembly;

FIG. 3 is a partially broken away side view, taken generally along the line 3-3 of FIG. 1, further illustrating the structure of the pump system;

FIG. 4 is a sectional view taken on an enlarged scale along line 4-4 of FIG. 3 with the reservoir assembly omitted for clarity of illustration, showing the relationship between a rotor assembly, intake passages for conducting fluid to the rotor assembly, and inlet passages through which fluid flows into the intake passages;

FIG. 5 is a sectional view, taken along the line 55 of FIG. 4, further illustrating the relationship of the intake passages to the rotor assembly;

FIG. 6 is a schematic pictorial illustration of the intake passages;

FIG. 7 is a schematic illustration, taken generally along the line 7 -7 of FIG. 6, depicting the elevational configuration of one of the intake passages;

FIG. 8 is a sectional view, taken along line 8-8 of FIG. 4, illustrating the configuration of a discharge passage and the relationship of a flow control valve assembly thereto;

FIG. 9 is a schematic pictorial illustration of the discharge passage;

FIG. 10 is an elevational view of one end plate of the pump assembly;

FIG. 11 is a sectional view, taken along the line ll-ll of FIG.10, further illustrating the structure of the end plate;

FIG. 12 is a sectional view, taken along the line l2l2 of FIG. 8, further illustrating the structure of the flow control valve assembly;

FIG. 13 is a sectional view, taken on an enlarged scale along the line 13-13 of FIG. 1, illustrating the structure of a flow restriction associated with the flow control valve assembly of FIG. 12 to provide a pressure differential in the discharge passage;

FIG. 14 is a sectional view, taken on an enlarged scale along the line l4-l4 of FIG. 1, illustrating the structure of a bypass valve assembly;

FIG. 15 is a broken away sectional view, somewhat similar to FIG. 4, illustrating the relationship of the bypass valve assembly to the flow restriction shown in FIG. 13.

FIG. 16 is a partially exploded view illustrating the relationship between a pair of end plates and the rotor assembly when the rotor assembly is to be driven in a counterclockwise direction; and

FIG. 17 is a partially exploded view illustrating the relationship of the end plates to the rotor assembly when the rotor assembly is to be driven in a clockwise direction.

The present invention provides an improved pump system which is adaptable for use in connection with different drive arrangements to provide a relatively large flow of fluid at a relatively high pressure. Although a pump system embodying the present invention can be used to supply high-pressure fluid in many different types of environments, the pump system is particularly well adapted for use in trucks and other types of vehicles having heavy duty power steering units. The pump system includes a pump assembly 20 (FIG. 1) which is connected in fluid communication with a main or primary external system, such as the power steering unit of a vehicle, by a fluid conduit 22. The pump assembly 20 is connected in fluid communication with an auxiliary or secondary external system, such as a fluid cooling unit or device, by a conduit 24. Fluid is supplied to the pump assembly 20 from a reservoir assembly 28 into which fluid flows from the external systems through a fluid return conduit 30. The fluid which is returned to the reservoir assembly 28 is advantageously cleaned by a filter 32 (FIG. 2) mounted in a main body portion 34 of the fluid reservoir assembly.

It is contemplated that the pump system will be utilized with many different types of engines and will, therefore, be mounted in various orientations relative to the engine and associated equipment. To facilitate this mounting of the pump system, the reservoir assembly 28 is adapted to be mounted in different positions relative to a housing 38 of a pump assembly 20. Thus, the reservoir assembly 28 can be moved or rotated relative to the pump assembly 20, from the relationship shown in solid lines in FIG. 1 to another relationship such as is shown in dashed lines in FIG. 1. To facilitate this movement of the reservoir assembly 28 relative to the pump assembly 20, the reservoir assembly includes a generally cylindrical portion 42 (see FIG. 3) which circumscribes the housing 38 and sealingly engages an annular seal 43 mounted on a rim 44 of the housing (FIG. 3). Once it is located in a desired position, the reservoir assembly 28 is retained against rotation relative to the pump assembly 20 by suitable connectors, one of which is indicated at 45 in FIG. 3. It should be noted that the conduits 22 and 24, for connecting the pump assembly 20 in fluid communication with the associated external systems, are on a forward end portion of the pump assembly and do not interfere with rotation of the reservoir assembly 28 relative to the pump as sembly.

In order to further increase the versatility of the pump system, the fluid return conduit 30 can be mounted on either the left side of the pump assembly, as shown in solid lines in FIG. 1, or on the right side, as shown in dashed lines in the upright view of FIG. 1. To enable the fluid return conduit 30 to be so mounted, the sides of the main body portion 34 are provided with mounting bosses or areas 46 and 48. In addition, it is contemplated that the main body portion 34 of the reservoir assembly 28, could if desired, be mounted away from the pump assembly 20 and connected to a generally cylindrical housing section, similar to the portion 42, by a suitable conduit.

The pump assembly 20 receives fluid at a relatively low pressure from the fluid reservoir assembly 28 and discharges the fluid at a relatively high pressure to associated external systems through the conduits 22 and 24. To provide this pressure increase, the pump assembly 20 includes a rotor assembly 52 (FIG. 4) located in a main pumping chamber 53 and circumscribed by a cam 54 which is fixedly mounted in the housing 38. The rotor assembly 52 receives fluid at a relatively low pressure from a pair of intake passages 58 and 60 which conduct the fluid to radially opposite sides of the rotor assembly (see FIGS. 4 and Fluid is discharged at relatively high pressure from the rotor assembly 52 to a discharge passage 62 (see FIG. 8) located adjacent to a forward end portion of the pump assembly 20.

The rotor assembly 52 provides this increase in pressure by means of a rotatable carrier 66 which is fixedly secured by a pin 67 to a drive shaft 68 (FIG. 4) driven by a suitable drive assembly (not shown). The carrier 66 includes a plurality of generally radially extending teeth 72 (FIG. 4) which drivingly engage rollers 74. The rollers 74 in turn sealingly engage an inner surface 75 of the cam 54 to define a plurality of axially extending pumping pockets 76. Upon rotation of the carrier 66, the rollers 74 are moved radially inwardly by the cam 54 to decrease the size of the pumping pockets or chambers 76 as the pockets are moved away from outlet or exit portions 80, 82, 84 and 86 of the intake passages 58 and 60 (see FIGS. 4, 5 and 6) by rotation of the carrier. The decrease in size of the pumping pockets 76 causes a corresponding increase in fluid pressure within the pockets so that when the pumping chambers or pockets are aligned with radially opposite entrance or inlet portions 90 and 92 of the discharge passage 62 (see FIGS. 8 and 9), fluid flows out of the pumping pockets through the discharge passage 62 to the associated external systems. Since the operation of the rotor assembly 52 is well known to those skilled in the art, it is believed that a further description of this operation is not required at this time.

To reduce pressure losses as fluid flows from the reservoir assembly 28 into the intake passages 58 and 60 through inlet passages 96 and 98 (FIG. 4), the inlet passages accelerate the fluid. To this end, each of the inlet passages 96 and 98 tapers inwardly from a relatively large, outer mouth or base 106 to a relatively small, inner end or opening 107. It should be noted that the inlet passages 96 and 98 are positioned so as to be connected in fluid communication with the cylindrical portion 42 of the reservoir assembly 28 regardless of the position in which the reservoir assembly is mounted relative to the pump assembly 20.

The intake passages 58 and 60 provide for a controlled reduction in fluid velocity with a minimum of frictional losses as fluid flows from the inlet passages 96 and 98 to the exit or discharge portions 80 through 86 of the intake passages, to thereby increase the fluid pressure at the exit or discharge portions. Accordingly inlet portions 102 and 104 of the intake passages flare axially outwardly to intermediate portions 108 and 110 (see FIGS. 4, 6 and 7) which are connected with the exit or discharge portions 80 through 86 located at opposite ends of the rotor assembly 52. The cross-sectional areas of the inlet portions 102 and 104 increase in a direction toward the intermediate portions and 110 so that the cross-sectional areas of the inlet portions are substantially the same as the crosssectional areas of the intermediate portions 108 and 110 at their junction. (See FIG. 6 where the general configuration if the intake passages is shown in solid lines.) This gradual increase in cross-sectional areas results in a decrease in velocity and a corresponding increase in pressure as fluid flows through the inlet portions 102 and 104 into the intermediate portions 108 and 110 of the intake passages 58 and 60.

In order to minimize the resistance to fluid flow into the rotor assembly 52, the exit or discharge portions through 86 of the intake passages 58 and 60 extend radially inwardly for equal distances at opposite ends of the rotor assembly. To this end, the intermediate portions 108 and of the intake passages 58 and 60 extend beyond the opposite ends of the rotor assembly 52 (see FIGS. 5 and 6) where the exit or discharge portions 80 through 86 of the intake passages are connected in fluid communication with the main pumping chamber 53 through inlet ports or areas 111 and 112 in end plates 114 and 116 (see FIGS. 5, l0 and 16). It should be noted that the end plates 114 and 116 are cut away to provide relatively large inlet ports or areas 111 and 112 to enable a relatively large volume of fluid to flow into the pumping pockets 76 from the intake passages 58 and 60.

When the pumping pockets 76 are rotated away from the radially opposite intake ports or areas 111 and 112 to radially opposite discharge ports or areas 128 and 130 in the end plates 114 and 116 (see FIGS. 8, 10, 11 and 16), fluid flows through the discharge areas or ports into the entrance or inlet portions 90 and 92 of the discharge passage 62 (see FIGS. 8 and 9). The fluid then flows from the entrance or inlet portions 90 and 92 of the discharge passage 62 through a generally annular connector portion 134 to an outlet portion 138 of the discharge passage. The fluid continues its flow to the external systems through an outlet portion 142 of the discharge passage 62 (see FIGS. 9 and 13).

To minimize operating stresses on the rotor assembly 52, the pressure against axially opposite ends or faces of the rotor assembly should be equalized. To this end, the end plates 114 and 116 are mirror images of each other (see FIGS. 16 and 17). Thus, the inlet ports 111 and 112 of the end plate 116 (FIGS. 10, 16 and 17) are of substantially the same size as the inlet ports 111 and 112 of the end plate 114 (FIGS. 16 and 17). Similarly, the discharge ports 128 and 130 of the end plate 116 (FIGS. 10, 11, 16 and 17) are of substantially the same size as the discharge ports 128 and 130 of the end plate 114.

To prevent leakage between the inlet ports 111 and 112 and the discharge ports 128 and 130, the discharge ports are circumscribed by seals 144 (see FIGS. 10, 11, 16 and 17). When the pump assembly 20 is assembled as shown in FIG. 8, the seal 144 on the end plate 114 sealingly engages the housing 38 while the seal 144 on the end plate 116 sealingly engages a cover plate 146. Of course, the area enclosed by the seals 144 on the end plate 114 is equal to the area enclosed by the seals 144 on the end plate 116. The area circumscribed by seals 144 is approximately equal to the area which is subjected to high pressure on the rotor side of end plates 114 and 116, thus equalizing the pressure forces on the end plates and minimizing their distortion. Minimizing deflection and other distortion of the end plates 114 and 116 significantly reduces internal leakage and results in higher pump efficiency. A known pump design pressurizes the entire back forces of the end plates 114 and 116 which results in a net force inward and requires stronger end plates to prevent too much inward deflection.

In order to maintain the output of the pump assembly 20 substantially constant over its operating range, a flow control valve assembly 148 (see FIGS. 8 and 12) is provided for diverting a portion of the fluid flow from the discharge passage 62 to the intake passages 58 and 60 when the fluid flow rate from the pump assembly reaches a predetermined maximum amount. To this end, the flow control valve assembly 148 includes a valve body 152 slidably mounted in a bore 154 located between the inlet portions 102 and 104 of the intake passages 58 and 60 (FIGS. 4 and 12). The valve body 152 is normally urged to the closed position shown in FIGS. 8 and 12 under the influence of both a spring 158 and fluid pressure in a chamber 160 formed in the bore 154 between a rearward end portion 162 of the valve body 152 and a plug 164. However, the valve body 152 is urged toward an open position by the pressure of discharge fluid from the rotor assembly 52 against a forward end 168 of the valve body 152. When the rate of fluid flow from the pump assembly reaches the predetermined maximum amount, the pressure against the forward end 168 of the valve body 152 urges the valve body rearwardly in the bore 154 against the influence of the spring 158 and pressure in the chamber 160. This movement of the valve body 152 opens the flow control valve assembly 148 and diverts fluid from the discharge passage 62 to the intake passages 58 and 60 to thereby maintain the fluid output in the pump assembly 20 substantially constant.

To provide for a smooth combined flow to the rotor assembly 52 of fluid diverted by the flow control valve assembly 148 and fluid from the reservoir assembly 28, the diverted fluid enters the inlet portions 102 and 104 of the intake passages 58 and 60 at locations adjacent to where the inlet passages 96 and 98 open into the intake passages. Thus, transverse passages 170 and 172 (see FIGS. 4 and 12) extend between the bore 154 and the inlet portions 102 and 104 of the intake passages 58 and 60. To promote a merging of the diverted fluid and the fluid from the reservoir assembly 28, the passages 170 and 172 open into the intake passages 58 and 60 adjacent to the ends 108 of the inlet passages 96 and 98. A plurality of annular lands 178 extend around the valve body 152 to prevent fluid flow between the discharge passage 62 and chamber 160 when the flow control valve assembly 148 is in the closed condition.

To provide for a decrease in the fluid pressure in the chamber 160 as the rate of flow of fluid to the external systems increases, a flow restriction means 184 (FIG. 13) is mounted in the outlet portion 142 of the discharge passage 62. In the present embodiment of the invention, the flow restriction means 184 is a nozzle 188 having a converging end portion 190 into which fluid flows from the outlet portion 138 of the discharge passage 62. The fluid then flows through a throat portion 192 of the nozzle 188 into a diverging end portion 194 of the nozzle. As the fluid flows through the converging end portion 190 of the nozzle to the throat 192, the velocity of the fluid is increased with a corresponding decrease in pressure until the throat portion 182 is reached. Of course, the greater the flow rate through the nozzle 188, the greater will be the velocity of the fluid at the throat portion 192 and the lower the fluid pressure. After flowing through the throat portion 192, the fluid enters the diverging end portion 194 of the nozzle and the velocity of the fluid decreases with a corresponding increase in pressure. The converging-diverging configuration of the nozzle 188 results in a minimum pressure loss in the fluid flowing through the nozzle and a resulting minimum temperature rise in fluid.

The fluid pressure at the throat portion 192 is communicated to the chamber 160 by means of a plurality of passages 200 and 202 (see FIGS. 8 and 13) forming a pressure tap extending from an annular chamber 204 (FIG. 13) which is connected in fluid communication with the throat portion 192 of the nozzle 188 by a passage 208. Since the fluid pressure at the throat portion 192 of the nozzle 188 decreases with an increasing flow rate, the fluid pressure in the chamber 204, pressure tap, and chamber 160 decreases with an increasing flow rate. Of course, as the flow rate increases the fluid pressure in discharge passage 62 increases as a result of the flow resistance of the external circuit, until the fluid pressure is sufficient to overcome the combined effects of the relatively lowfluid pressure in the chamber 160 and the spring 158. The valve body 152 is then moved to the open position so that fluid from the discharge passage 62 is diverted through the transversely extending passages 170 and 172 to the inlet passages 58 and 60 (FIG. 12). For those who are interested, the relationship between the flow control valve assembly 148 and the flow restriction means 184 is more fully set forth in my U.S.

Pat. No. 3,384,020 and, therefore, will not be further described herein.

The discharge fluid from the rotor assembly 52 flows through the discharge passage 62 and conduit 22 (see FIG. 1) to the main external system, such as a power steering assembly, until the main external system is shut off. When the main external system is shut off, the fluid pressure in the discharge passage 62 tends to increase. This increase in pressure operates a bypass or relief valve assembly 214 (FIG. 14) to direct the fluid to the conduit 24 and the auxiliary external system, such as a fluid cooler unit. Accordingly, the bypass valve assembly 214 is connected in fluid communication with the passage 142 by a passage 216. The flow of fluid through the passage 216 and conduit 24 to the auxiliary external system is normally blocked by a valve 220 which is pressed against a valve seat 222 by a spring 224. When the main external system is shut off, the fluid pressure in the passages 142 and 216 increases and the valve 220 is moved away from the seat 222 to enable fluid to flow through the bypass or relief valve assembly 214 to the conduit 24 and the auxiliary external system. This promotes relatively efficient, low-temperature operation of the pump assembly 20 by cooling the oil before it is returned to the reservoir assembly 28. The valve 220 has a cone-shaped seat 224 to provide a substantially constant relief valve pressure with changes in pump speed and fluid flow.

The flow restriction assembly 184 and flow control valve assembly 148 cooperate to maintain the fluid flow to both the main external system and the auxiliary external system substantially constant throughout the operating range of the pump assembly 20. To this end the flow restriction assembly 184 is located upstream from the bypass or relief valve assembly 214 (see FIG. 15 taken in conjunction with FIG. 13) so that fluid flowing through the passage 216 and bypass valve assembly 214 to the auxiliary external system must flow through the nozzle 188 before entering the passage 216. Therefore, regardless of which external system the fluid is flowing to at any given time, the relief valve assembly 148 is operable to maintain the flow rate at or below the predetermined maximum flow rate.

An internal bypass system 226 is advantageously provided in the housing 38 (FIG. 14). The internal bypass system can be used to bypass fluid directly to the reservoir through a passage 228 formed in the housing 38 and connected in fluid communication with the bypass or relief valve assembly 214. When the internal bypass system 226 is utilized, the external conduit 24 can be eliminated with a saving in installation cost and time. Of course, the internal bypass system 226 will not be used when it is necessary to provide external means for cooling the fluid.

As was previously explained, it is contemplated that the pump system will be used in connection with difierent types of drive assemblies and engine structures. In addition, it is contemplated that the pump system will be utilized with both clockwise and counterclockwise drive assemblies. To enable the pump system to be so used, it is imperative that the rotor assembly 52 of the pump assembly 20 be adaptable for rotation in either a clockwise or a counterclockwise direction. To provide this adaptability, the end plates 114 and 116 are mirror images of each other and have similar inlet portions or areas 111 and 112 which cooperate with the intake passages 58 and 60 in generally the same manner. In addition, the discharge portions 128 and 130 of the end plates 114 and 116 are adapted to cooperate with the inlet portions and 92 of the discharge passage 62 in generally the same manner.

This similarity in structure between the end plates 114 and 116 enables the end plates, rotor assembly 52 and cam 54 to be reversed relative to the housing 38. Thus, the pump assembly 20 can be assembled in a first manner, illustrated in FIG. 16, wherein the rotor assembly 52 is adapted to be driven in a counterclockwise direction when viewed from rearward portion of the pump assembly or a second manner, illustrated in FIG. 17, wherein the rotor assembly 52 is adapted to be driven in a clockwise direction. Reversing the end plates 114 and 116, rotor assembly 52 and cam 54 results in the seals 144 on the end plate 114 being moved from a position wherein the seals abut the housing 38 in the manner shown in FIGS. 8 and 16 to a position wherein the seals abut the cover plate 146. Similarly, when the pump assembly is changed from counterclockwise to clockwise drive, the end plate 1 16 is moved from a position adjacent the cover plate 146 (see FIGS. 4, 7 and 16) to a position adjacent the housing 38 (see FIGS. 17). It should be noted that reversing the rotor assembly 52 and cam 54 positions the teeth 72 of the rotor assembly so that they always slope forwardly in the direction of rotation. Thus, the teeth 72 slope in a generally counterclockwise direction (see FIGS. 13 and 16), when the carrier 66 is to be driven in a counterclockwise direction and the teeth slope in a generally clockwise direction (see FIG. 17) when the carrier is to be driven in a clockwise direction.

Once the pump assembly has been assembled, the end plates 114 and 116 and cam 54 are held against rotation by a lock pin 240 (see FIGS. 16 and 17). To this end, the pin 240 extends through U-shaped slots 244 and 246 formed in the outer portion of the end plates 114 and 116 and a U-shaped slot 250 formed in an outer portion of the cam 54. The forward end portion of the pin 240 engages a hold 254 in the housing 38 and the rearward end portion of the pin 140 engages a slot 256 in the cover plate 146 to securely hold the end plates 114 and 116 and cam 54 in a predetermined relationship relative to the housing 38 and cover plate. The cover plate 146 is in turn held in position by a lock ring 260 (see FIGS. and 8).

When the pump assembly 20 is adapted to be driven in a clockwise direction, the position of the slots 244 and 246 are reversed from the position shown in FIG. 16 to the position shown in FIG. 17. The forward end portion of the locking pin 240 then engages a hold 264 in the housing 38 while the rearward end portion of the locking pin engages a slot 266 in the cover plate 146. Although it is preferred to make the pump assembly 20 with only a single hole in the housing 38 to receive the forward end portion of the locking pin 240 and a single slot in the cover plate 146 to receive the rearward end portion of the locking pin 240, it is contemplated that the pump assembly could, if desired, be manufactured with two sets of holes and slots, one for a counterclockwise drive arrangement and another for a clockwise drive arrangement.

In view of the foregoing remarks, it can be seen that the pump assembly 20 can be made with a large capacity so as to provide a relatively large fluid flow to an associated external stem when the pump assembly is being driven at a relatively low speed. The relatively large capacity of the pump assembly 20 results from the provision of large inlet portions or areas 111 and 112 in each of the end plates 114 and 116 to enable fluid to readily flow into the pumping chambers 76 of the rotor assembly 66. This flow of fluid is promoted by the intake passages 58 and 60 which increase in a cross-sectional area in a direction of fluid flow as to reduce the velocity and increase the pressure of the fluid at the inlet areas of the rotor assembly 52. In addition, the inlet passages 96 and 98 taper inwardly toward the inlet portions of the associated intake passages 58 and 60 to gradually accelerate the fluid as it enters the intake passages at the high-velocity low-pressure inlet portions 102 and 104 of the intake passages.

The fluid pressure on the rotor assembly 52 and the end plates 114 and 116 is balanced by exposure of equal areas of the rotor assembly and end plates to the pressure of the inlet fluid and by exposure of equal areas of the rotor assembly and end plates to the pressure of the discharge fluid. The seals 144 mounted on the end plates 114 and 116 prevent a leakage of a relatively high-pressure discharge fluid from the discharge portions 128 and 130 of the end plates to the inlet portions 111 and 112 ofthe end plates.

The pump assembly 20 directs fluid to a main external system, such as a power steering unit, through a conduit 22. However, when the main external system is shut oft", a bypass valve assembly 214 is operated to direct the fluid to an auxiliary external system, such as a fluid cooler unit, through the conduit 24. The flow of fluid to these external systems is maintained at or below a predetermined rate by the cooperation of a flow restriction assembly 184 and a relief valve assembly 148. To minimize operating temperatures and provide a discharge passage pressure which decreases as the rate of flow increases, the flow restriction means 184 includes a converging diverging nozzle 188 with a throat portion 192 which is connected in fluid communication with a pressure tap formed by passages 200 and 202 through the housing 38. Pressure in the throat portion 192 is transmitted by the pressure tap to one side of the flow control valve assembly 148 while the opposite side of the flow control valve assembly is exposed to the pressure of the discharge fluid before it enters the nozzle 188. When the flow rate through the nozzle 188 reaches a predetermined maximum amount, the pressure in the'throat 192 will be relatively low so that the pressure differential across the relief valve assembly 148 is sufficient to operate the relief valve assembly to an open condition and thereby divert discharge fluid to the intake passages 58 and 60.

The pump system is versatile and adapted to be utilized with different types of drive assemblies. To this end, the reservoir assembly 28 is rotatable relative to the pump assembly 20 so that the pump assembly can be mounted in various orientations relative to a drive assembly. The versatility of the reservoir assembly 28 is further increased by the adaptability of the fluid return conduit 30 to mounting on either side of the fluid reservoir assembly. In addition, the pump assembly 20 is adapted to be driven either in a counterclockwise or clockwise direction, depending upon the orientation of the rotor assembly 52, cam 54 and end plates 114 and 116 in the housing 38.

Iclaim:

1. A pump assembly comprising:

a housing,

rotor means rotatably mounted in said housing for receiving fluid at one pressure and discharging fluid at a higher pressure,

intake passage means for conducting a flow of fluid to said rotor means at one diametrical location thereof from a source of fluid, and

discharge means for conducting a flow of fluid from said rotor means,

said intake passage means including, means defining an inlet passage communicating with a source of fluid,

an inlet chamber portion connected in fluid communication with said inlet passage,

an intermediate chamber portion connected to said inlet portion and having an axial extent which is at least equal to the axial extent of said rotor means,

said inlet chamber portion having surfaces for directing fluid circumferentially of said rotor to said intermediate chamber portion and being defined in part by facing radi ally spaced circumferentially extending surfaces and by facing axially spaced circumferentially extending surfaces, certain of said spaced surfaces flaring relatively as they extend from a part of the inlet chamber having a relatively small cross-sectional area and into which fluid flows from said inlet passage to a relatively large crosssectional area which is substantially the same as the crosssectional area of said intermediate portion at a junction of said inlet and intermediate chamber portions to thereby provide for a reduction in fluid velocity as the fluid flows through said inlet portion and into said intermediate portion.

2. A pump assembly as defined in claim 1 wherein said housing comprises:

a one-piece cast part and said surfaces are formed on said part.

3. A pump assembly as set forth in claim 1 wherein:

said inlet passage means tapers as it extends toward the inlet chamber to accelerate fluid flowing from the source of fluid to said inlet chamber.

4. A pump assembly as set forth in claim 1 wherein the source of fluid includes:

a reservoir means mounted on said housing for holding fluid, said reservoir means being adapted to be mounted in any one of a plurality of positions relative to said housing, and connector means for securing said reservoir means in any one of the plurality of positions relative to said housing. 5. A pump assembly comprising: a housing, rotor means rotatably mounted in said housing for receiving fluid at one pressure and discharging fluid at a higher pressure, intake passage means for conducting a flow of fluid to said rotor means from a source of fluid, and discharge means for conducting a flow of fluid from said rotor means, said intake passage means including, first intake passage means for conducting fluid to axially opposite portions of said rotor means at one diametrical location thereof, and second intake passage means for conducting fluid to axially opposite portions of said rotor means at another diametrical location thereof opposite the one diametrical location, said respective first and second intake passage means each including, means defining an inlet passage communicating with a source of fluid, an inlet chamber portion connected in fluid communication with said inlet passage, an intermediate chamber portion connected to said inlet chamber portion and having an axial extent which is at least equal to the axial extent of said rotor means, and first and second outlet portions extending from said intermediate chamber portions inwardly adjacent respective opposite axial sides of said rotor means to enable fluid to enter said rotor means from both axial sides thereof, said inlet portion having surfaces directing fluid circumferentially of said rotor to said intermediate portion and being defined in part by facing radially spaced circumferentially extending surfaces and by facing axially spaced circumferentially extending surfaces, certain of said spaced surfaces flaring relative to said rotor means from a part of the inlet chamber having a relatively small crosssectional area and into which fluid flows from said inlet passage to a relatively large cross-sectional area which is substantially the same as the cross-sectional area of said intermediate portion at a junction of said inlet and intermediate chamber portions to thereby provide for a reduction in fluid velocity as the fluid flows through said inlet portion and into said intermediate portion. 6. A pump assembly as set forth in claim 5 wherein said rotor means is adapted to be positioned in said housing for rotation in a first direction relative to said housing and to be positioned in said housing for rotation in a second direction relative to said housing to thereby enable said pump assembly to be utilized in association with drive assemblies having different directions of rotation.

7. A pump assembly as set forth in claim 5 wherein said source of fluid is a reservoir means mounted on said housing for holding fluid, said reservoir means and said housing having cooperating portions supporting said reservoir on said housing for rotation relative thereto, and connector means for securing said reservoir means in any one of a plurality of positions relative to said housing.

8. A pump assembly as defined in claim 5 wherein said inlet passages are generally conical in shape and narrow as they extend toward said inlet chambers to thereby accelerate the flow of fluid therethrough.

9. A pump assembly comprising:

a housing,

rotor means located in a pumping chamber and rotatably mounted in said housing for receiving fluid at one pressure and discharging fluid at a higher pressure, said rotor means having a first position in a first orientation in said housing when said rotor means is rotated in one direction and having a second position in a second orientation in said housing when said rotor means is rotated in a direction opposite from said one direction,

first and second end plate means mounted in said housing at opposite ends of said rotor means and cooperating therewith to at least partially define a pumping chamber,

said first and second end plate means each including, inlet portions through which fluid flows into the pumping chamber and outlet portions through which fluid flows from the pumping chamber,

intake means for conducting a flow of fluid from a source of fluid to said inlet portions of said first and second end plate means,

discharge means for conducting fluid from said outlet por tions of said first and second end plate means, and

means for retaining said first and second end plate means in a predetermined relationship with said rotor means when said rotor means is positioned in said first orientation relative to said housing and for retaining said first and second end plate means in the same predetermined relationship with said rotor means when said rotor means is positioned in said second orientation relative to said housing,

said inlet and discharge portions of said first and second end plate means including openings through which fluid flows to and from said rotor means, said openings being oriented in a first relationship relative to said intake and discharge means when said rotor means is rotated in said one direction and in another relationship relative to said intake and discharge means when said rotor means is rotated in said direction opposite from said one direction. 

1. A pump assembly comprising: a housing, rotor means rotatably mounted in said housing for receiving fluid at one pressure and discharging fluid at a higher pressure, intake passage means for conducting a flow of fluid to said rotor means at one diametrical location thereof from a source of fluid, and discharge means for conducting a flow of fluid from said rotor means, said intake passage means including, means defining an inlet passage communicating with a source of fluid, an inlet chamber portion connected in fluid communication with said inlet passage, an intermediate chamber portion connected to said inlet portion and having an axial extent which is at least equal to the axial extent of said rotor means, said inlet chamber portion having surfaces for directing fluid circumferentially of said rotor to said intermediate chamber portion and being defined in part by facing radially spaced circumferentially extending surfaces and by facing axially spaced circumferentially extending surfaces, certain of said spaced surfaces flaring relatively as they extend from a part of the inlet chamber having a relatively small cross-sectional area and into which fluid flows from said inlet passage to a relatively large cross-sectional area which is substantially the same as the cross-sectional area of said intermediate portion at a junction of said inlet and intermediate chamber portions to thereby provide for a reduction in fluid velocity as the fluid flows through said inlet portion and into said intermediate portion.
 2. A pump assembly as defined in claim 1 wherein said housing comprises: a one-piece cast part and said surfaces are formed on said part.
 3. A pump assembly as set forth in claim 1 wherein: said inlet passage means tapers as it extends toward the inlet chamber to accelerate fluid flowing from the source of fluid to said inlet chamber.
 4. A pump assembly as set forth in claim 1 wherein the source of fluid includes: a reservoir means mounted on said housing for holding fluid, said reservoir means being adapted to be mounted in any one of a plurality of positions relative to said housing, and connector means for securing said reservoir means in any one of the plurality of positions relative to said housing.
 5. A pump assembly comprising: a housing, rotor means rotatably mounted in said housing for receiving fluid at one pressure and discharging fluid at a higher pressure, intake passage means for conducting a flow of fluid to said rotor means from a source of fluid, and discharge means for conducting a flow of fluid from said rotor means, said intake passage means including, first intake passage means for conducting fluid to axially opposite portions of said rotor means at one diametrical location thereof, and second intake passage means for conducting fluid to axially opposite portions of said rotor means at another diametrical location thereof opposite the one diametrical location, said respective first and second intake passage means each including, means defining an inlet passage communicating with a source of fluid, an inlet chamber portion connected in fluid communication with said inlet passage, an intermediate chamber portion connected to said inlet chamber portion and having an axial extent which is at least equal to the axial extent of said rotor means, and first and second outlet portions extending from said intermediate chamber portions inwardly adjacent respective opposite axial sides of said rotor means to enable fluid to enter said rotor means from both axial sides thereof, said inlet portion having surfaces directing fluid circumferentially of said rotor to said intermediate portion and being defined in part by facing radially spaced circumferentially extending surfaces and by facing axially spaced circumferentially extending surfaces, certain of said spaced surfaces flaring relative to said rotor means from a part of the inlet chamber having a relatively small cross-sectional area and into which fluid flows from said inlet passage to a relatively large cross-sectional area which is substantially the same as the cross-sectional area of said intermediate portion at a junction of said inlet and intermediate chamber portions to thereby provide for a reduction in fluid velocity as the fluid flows through said inlet portion and into said intermediate portion.
 6. A pump assembly as set forth in claim 5 wherein said rotor means is adapted to be positioned in said housing for rotation in a first direction relative to said housing and to be positioned in said housing for rotation in a second direction relative to said housing to thereby enable said pump assembly to be utilized in association with drive assemblies having different directions of rotation.
 7. A pump assembly as set forth in claim 5 wherein said source of fluid is a reservoir means mounted on said housing for holding fluid, said reservoir means and said housing having cooperating portions supporting said reservoir on said housing for rotation relative thereto, and connector means for securing said reservoir means in any one of a plurality of positions relative to said housing.
 8. A pump assembly as defined in claim 5 wherein said inlet passages are generally conical in shape and narrow as they extend toward said inlet chambers to thereby accelerate the flow of fluid therethrough.
 9. A pump assembly comprising: a housing, rotor means located in a pumping chamber and rotatably mounted in said housing for receiving fluid at one pressure and discharging fluid at a higher pressure, said rotor means having a first position in a first orientation in said housing when said rotor means is rotated in one direction and having a second position in a second orientation in said housing when said rotor means is rotated in a direction opposite from said one direction, first and second end plate means mounted in said housing at opposite ends of said rotor means and cooperating therewith to at least partially define a pumping chamber, said first and second end plate means each including, inlet portions through which fluid flows into the pumping chamber and outlet portions through which fluid flows from the pumping chamber, intake means for conducting a flow of fluid from a source of fluid to said inlet portions of said first and second end plate means, discharge means fOr conducting fluid from said outlet portions of said first and second end plate means, and means for retaining said first and second end plate means in a predetermined relationship with said rotor means when said rotor means is positioned in said first orientation relative to said housing and for retaining said first and second end plate means in the same predetermined relationship with said rotor means when said rotor means is positioned in said second orientation relative to said housing, said inlet and discharge portions of said first and second end plate means including openings through which fluid flows to and from said rotor means, said openings being oriented in a first relationship relative to said intake and discharge means when said rotor means is rotated in said one direction and in another relationship relative to said intake and discharge means when said rotor means is rotated in said direction opposite from said one direction. 